Treatment of complex ores by flotation



Patented 6, 1931 PATENT OFFICE wrrnnnn scan-Ea, or BOGHUM, enanm TREATMENT OF COMPLEX OBES BY FLOTAT'ION No Drawing. Application filed September 1 8, 1929, Serial No. 898,584, and in Germany September 22, 1928.

The invention relates to the treatment of complex ores containing sulfides of zinc in the presence of other metalliferous sulfides such as lead or copper sulfides where the collective afiinity of oils and similar substances is utilized to make a separation, especially to the so called froth flotation process in which the substances adhering to the oil are separated from the pul by the use of a gas (such as air) in form 0 a froth. In these procalkali, are

esses it is known to influence the flotative ualities by the use of reagents in addition to t e oils. These known reagents, such as cyanide of otassium, sulfides and sulfites of own to influence the flotative qualities, so that for instance it is possible to first separate the leador copper sulfide in the froth and to separate subsequently after having compensated the action of these reagents, and adding other reagents, the zinc sulfides in the froth. The action of the reagents, having the eifect to keep down certain sulfides, is commonly known as depressing action While those reagents which compensate the action of the reagents of the first-mentionedkind, and effect the separation of the depressed mineral, are called anti-depressing rea ents.

It has been foun that a very effective depressing action on the zinc sulfides and at the same time an activating effect on the copper or lead sulfides, is produced by the add1t1on of salts of the hyposulfurous acid, that is of hyposulfites of the formula:

the same or different metals.

These hyposulfites are 'to be clearly distinguished from the thiosulfates of the formula R 8 0, which are sometimes erroneously' called also hyposulfites. The complex hyposulfites, especially those in which R is an alkali metal and R a base metal, are generally more efiective as depressors of the zinc mineral while the simple salts in which R and R are the same metals, are generally more efiective as activator of the lead and copper minerals.

In numerous cases it is of advantage to use hyposulfites in the resence of other reagents which liberate '0 -ions or H-ions in thepulp it may be useful to add these reagents ,toget er with the hyposulfites or before or afterwards. The hydroxyl ions may be furnished by bases or by salts having an alkaline reaction or by any compounds either organic or inorganic which in the process give rise toan alkaline reaction. The hydrogen ions may be furnished by acids or salts having an acid reaction or by compounds either organic or' inorganic which in the process give rise to an acid reaction. When the reagents which liberate hydroxyl or hydrogen ions are added after the treatment of the pulp with the hydrosulfites, they assist in the reactivating of the blende, and allow the flotation of the zinc sulfide previously separated from the pulp. The principal advantage of the hyposulfites over other known rea cuts of the de- Ewample N 0. 1

100 gr. of a lead-zinc complex ore with quartzitic gangue were ground to 100 mesh fineness and diluted with four parts of water. gr. of a hyposulfite of the following formula (Na Zn)(S O 2 were added and 1.5 gr. sodium silicate, furnishing hydroxyl ions, and several drops of-ahard-wood tar oil and a pine oil were added. Then separation was made by producing a froth through the introduction of air under pressure and the following products were obtained:

3.5 weight lead-concentrate with- 71.4% Pb 5.4% Zn 96.5 weight zinc residues with.. 0.6% Pb 9.4% Zn 100.0 weight heads with 3.1% Pb 9.2% Zn The zinc residues were not further treated as the test should only demonstrate the activating action of the hyposulfites on the lead, and the depressing action on the zinc.

A parallel test was made in exactly the same manner and with exactly the same amount of ore but using 0.3 gr. sodium cyanide and 0.5 gr. zinc sulfate instead of the.

hyposulfite. The following products were obtained:

3.7 weight lend concentrate with G0.5% Pb 8.5% Zn 06.3 weight zinc residues with 0.8% Pb 9.2% Zn iEiE \;e ii;hi i, n;;l1:vn1i l 3.0% Pb 0.2% Zn [fa-ample N0. 53

9.1 weight lend iuiddlings wlth 25.2% P1) 81.4 weight zinc residues witl1 3.8% Pb 100.0 weight heads .with ..10.9% Pb 17.8% Zn A parallel test was made in exactly the same manner as before but using instead of the hyposulfite, 0.5 gr. sodium carbonate and 0.3 gr. cyanide of sodium and 0.4 gr. zinc sulfate. The following products were obtained:

7.0 weight lead concentraie with 2S.8% Pb 17.9% Zn 14.0 weight '72; lend middlings with 211.9/0 Pl) 18.5% Zn 78.4 weight zine residues with 7.2% Pb 17.7% Zn 100.0 weight heads with 10.9% Pb 17.8% Zn Having thus described my invention what I claim to protect is:

1. The step in the froth flotation process of treating finely divided zinc sulfides ore in the presence of other metalliferous ores to efl'ect a separation of the zinc sulfide mineral from the other minerals which comprises treating the ores with a flotation solution containing a metal salt of the hyposulfurous acid of the formula H S O. and subjecting the ore pulp to flotation whereby the zinc sulfides to be iepalll'ated are prevented from. adhering to the rot 2. The step in the froth flotation process of treating finely divided zinc sulfides ore in the presence of other metalliferous ores to effect a separation of the zinc sulfide mineral from the other minerals which comprises treating the ores with a flotation solution containing a complex metal salt of the hyposulfurous acid of the formula H 8 0 and subjecting the ore pulp to flotation whereby the zinc sulfides to be separated are prevented from adhering to the froth.

3. The step in the froth flotation process of treating finely divided zinc sulfides ore in the presence of other metalliferous ores to effect a separation of the zinc sulfide mineral from the other minerals which comprises treating the ores with a flotation solution containing a metal salt of the hyposulfurous acid of the formula H S O and substances containing hydroxyl ions, and subjecting the ore pulp to flotation whereby the zinc sulfides to be sfepalrated are prevented from adhering to the rot 1.

4. In the froth flotation process of treating finely divided zinc sulfides ore in the presence of other metalliferous ores to effect a separation of the zinc sulfide mineral from the other minerals which comprises treating the ores,

with a flotation solution containing a complex metal salt of the hyposulfurous acid of the formula H S O and substances containing hydroxyl ions, and subjecting the ore pulp to flotation'whereby the zinc sulfides to be separated are prevented from adhering to the froth.

5. The step in the froth flotation process of treating finely divided zinc sulfides ore in the presence of other metalliferous ores to eflect a separation of the zinc sulfide mineral from the other minerals which comprises treating the ores with a flotation solution containing a metal salt of the hyposulfurous acid of the formula H 8 0. and substances containing hydroxyl ions, whereby the zinc sulfides to be separated from the ore are prevented from adhering to the froth and thereafter adding to the solution a substance having hydrogen ions whereby the flotation of the zinc sulfides is permitted.

6. The step in the froth flotation process of treating finely divided zinc sulfide ore in the presence of other metalliferous ores to effect a separation of the zinc sulfide mineral from the other minerals which comprises treating the ores with a flotation solution containing a complex metal salt of the hyposulfurous acid of the formula H 820. and substances containing hydroxyl ions and subjecting the ore pulp to flotation, whereby the zinc sulfides to be separated from the ore are prevented from adhering to the froth and thereafter adding to the solution a substance having hydrogen ions whereby the flotation of the zinc sulfide is. permitted.

' DR. WILHELM SCI-IAFER. 

